I only know of one person who used to do scales for Grips, and he quit doing them because the knives are too hard to work with (nested partial liners, tiny screws, etc.).
I'd like to have a Grip & mini-Grip in something other than FRN too, but the closest I've been able to come is to buy a H&K 14210 & 14205. These knives are about the same size as the Grips and minis, but they're open construction with full liners and G10 scales. They are not "grippy" however. The G10 is very smooth (way too smooth) and they can be hard to hold on to at times.
They are tough, though, I'll give 'em that. I've dropped my 14210 onto a concrete patio because it's so damn smooth, but very little damage was done. I got a tiny dent (not a chip) in the G10, but it's nearly invisible now that I got the white concrete dust out of it.